1. Field of the Invention
The present invention relates to a fluidized bed water gas shift membrane reactor and a method for separating carbon dioxide using the same. More specifically, the present invention relates to a fluidized bed water gas shift membrane reactor provided on the back of a gasification reactor to produce a synthetic gas consisting of hydrogen and carbon monoxide by reaction of a solid hydrocarbon with water or oxygen, wherein the carbon monoxide present in an amount of 40 to 70 vol % in the synthesis gas reacts with steam in the presence of a catalyst to produce a mix gas of hydrogen and carbon dioxide, and the hydrogen is selectively isolated from the mix gas through a Pb—Cu shift membrane to increase the concentration of carbon dioxide present in the mix gas and separate the carbon dioxide, and a method for separating carbon dioxide using the same.
2. Description of the Related Art
In an attempt to solve recent problems such as global warming and rapid depletion of energy resources such as oil or natural gas, gasification to convert solid hydrocarbon materials such as fuels, waste materials, and biomass into synthetic gases as clean energies comes into the spotlight.
Gasification enables mass-production of hydrogen which is known as the most environmentally-friend energy source and low-cost treatment of greenhouse gases, as compared to conventionally-used combustion. Based on these advantages of gasification, many enterprises are attempting to develop gasification techniques. However, current processes for converting most of synthetic gases consisting of hydrogen and carbon monoxide into hydrogen and for separating carbon dioxide in the synthetic gas are generally complicated and entail high costs.
In addition, in the process of production of hydrogen using gasification, carbon monoxide is yielded in an amount more than hydrogen, depending on factors such as the type of solid hydrocarbon materials, gasifying agents, the type of reactors and operation conditions, and carbon dioxide is yielded in a low amount of 5-10 vol % and 15-30 vol % for dry-type gasification and wet-type gasification, respectively, and the ingredient present in the highest amount, 40-70 vol %, in the synthetic gas, is carbon monoxide.
Accordingly, development of processes for converting carbon monoxide contained in the synthetic gas into carbon dioxide and hydrogen in order to convert solid hydrocarbon materials into clean energies using gasification, and separating highly concentrated carbon dioxide is required.
The generally-used method for converting carbon monoxide into hydrogen is a fixed-bed water gas process wherein carbon monoxide reacts with vapor in the presence of catalysts, which is unsuitable for application to synthetic gases which contain 40-70 vol % of carbon monoxide. In addition, this method requires installation of additional equipment such as carbon dioxide absorbing tops which is currently developed to separate carbon dioxide, thus entailing an increase in gasification costs.
That is, Korean Patent Nos. 0612956 and 0462286 related to conventional water gas reactions are directed to water gas catalysts and Korean Patent No. 0816879 discloses a membrane reactor simultaneously performing water vapor modification and carbon monoxide removal, and a method for preparing hydrogen using the same. Also, Korean Patent Application No. 2004-0056403, related to a shift membrane similar to the present invention, discloses hydrogen production using a shift membrane reactor through conversion of dimethylether, which disadvantageously cannot solve problems associated with conversion into clean energy through gasification.
Accordingly, in order to produce clean energy resources through gasification of solid hydrocarbon materials, and separate and store carbon dioxide at low costs, a single gas reactor in which high-concentration carbon monoxide reacts with vapor to produce a mix gas containing an increased concentration of carbon dioxide, and hydrogen is separated from the mix gas to increase the concentration of carbon dioxide and a method for separating carbon dioxide using the same are required.